A pulse oximeter number is the most common thing people with COPD watch. Here’s what the numbers mean according to the FDA, NIH’s MedlinePlus and the American Thoracic Society (ATS), and what they don’t tell you. This guide is general information. Your own target comes from your clinician.
SpO2 ranges at a glance
| SpO2 reading | What the source says | Source |
|---|---|---|
| 95–100% | Typical for most healthy people | FDA, MedlinePlus |
| Somewhat lower | Can be acceptable with lung disease such as COPD; also lower at higher elevation | MedlinePlus, FDA |
| 92% or lower | Contact your provider | MedlinePlus |
| 88% or lower | Seek immediate medical attention | MedlinePlus |
MedlinePlus’s thresholds are general advice. If your care team has given you a personal plan, follow it.
When long-term oxygen is recommended (ATS 2020)
The ATS clinical practice guideline on home oxygen (Jacobs et al., 2020):
| Situation | ATS recommendation | Strength |
|---|---|---|
| COPD with severe chronic resting hypoxemia | Long-term oxygen at least 15 hours/day | Strong |
| COPD with moderate resting hypoxemia (SpO2 89–93%) | Suggests against long-term oxygen | Conditional |
| COPD or ILD with severe exertional hypoxemia | Suggests ambulatory oxygen | Conditional |
| ILD with severe chronic resting hypoxemia | Long-term oxygen at least 15 hours/day | Strong |
The guideline defines severe resting hypoxemia as PaO2 of 55 mm Hg or lower, or SpO2 of 88% or lower. It also counts PaO2 of 56–59 mm Hg or SpO2 of 89% when there’s dependent edema, hematocrit over 55%, or P pulmonale on ECG.
Why the oximeter number isn’t the whole story
- Accuracy: MedlinePlus says pulse oximetry can be 2–4% higher or lower than actual blood oxygen. Your provider may order an arterial blood gas (ABG) for a more accurate result (MedlinePlus).
- Factors that affect readings: poor circulation, skin pigmentation, skin thickness, skin temperature, tobacco use and fingernail polish (FDA).
- Context matters: the FDA says readings should be considered alongside signs and symptoms, and some people with low oxygen show no symptoms. Many OTC oximeters are general-wellness products the FDA hasn’t evaluated for clinical decisions.
- Symptoms of low oxygen include bluish lips, nails or face, shortness of breath, chest pain and a fast heart rate (MedlinePlus).
Tips for a reliable reading (FDA)
| FDA tip | Why it matters |
|---|---|
| Follow your provider’s advice on when and how often to check | Your plan defines what’s normal for you |
| Follow the manufacturer’s instructions | Devices differ |
| Hand warm, relaxed and held below heart level | Cold or tense hands reduce accuracy |
| Remove fingernail polish on that finger | Polish affects accuracy |
| Sit still; wait until the reading stops changing | Movement and early readings mislead |
| Write down the level, date and time | Lets you and your provider track changes |
Summarized from FDA Pulse Oximeter Basics. You can report a problem with an oximeter to the FDA through MedWatch.
Don’t self-adjust your flow
The FDA warns that “giving yourself too much or too little oxygen can be dangerous” and that a concentrator shouldn’t be used at home unless prescribed (FDA). If your readings are consistently below what your clinician expects, call them. Don’t just turn up the dial. If you use a pulse-dose portable unit, its setting numbers aren’t liters per minute. See pulse dose vs continuous flow.
Special situations
- Altitude: saturation falls at higher elevation (FDA). See oxygen at altitude and Denver.
- Sleep: levels can drop during sleep, and some POCs aren’t suitable at night. See POCs for sleeping.
- Exertion: the ATS guideline addresses exertional hypoxemia separately (table above).
Verdict
Use your oximeter to spot trends and warning signs, not to change your own prescription. Use 95–100% as the healthy reference, 92% or lower as the point to call your provider, and 88% or lower as the point to seek immediate care, unless your clinician has set a different plan. Bring a log of readings to appointments, and ask for an ABG if readings and symptoms don’t match.
Related: Medicare home oxygen coverage, oxygen concentrator buyer’s guide, home oxygen fire safety.